At 10:37 there was a loud bang followed by several seconds of shaking. I thought we'd just had a pretty big earthquake. I'm not usually scared by those things, but that one got my attention. It sounded like something exploded very nearby.
Reports are it was only 3.9, but it was centered down near San Juan Capistrano which isn't very far away. It was also fairly shallow - lots of energy released not too far away. Really rattled the house. The cat didn't care much for it either.